Copied from Debian.

From: Kamil Dudka <kdudka@redhat.com>
Date: Mon, 14 Sep 2015 18:24:56 +0200
Subject: fix infinite loop when extracting empty bzip2 data
Bug-Debian: https://bugs.debian.org/802160
Bug-RedHat: https://bugzilla.redhat.com/show_bug.cgi?id=1260944
Origin: other, https://bugzilla.redhat.com/attachment.cgi?id=1073339

---
 extract.c | 6 ++++++
 1 file changed, 6 insertions(+)

--- a/extract.c
+++ b/extract.c
@@ -2728,6 +2728,12 @@
     int repeated_buf_err;
     bz_stream bstrm;
 
+    if (G.incnt <= 0 && G.csize <= 0L) {
+        /* avoid an infinite loop */
+        Trace((stderr, "UZbunzip2() got empty input\n"));
+        return 2;
+    }
+
 #if (defined(DLL) && !defined(NO_SLIDE_REDIR))
     if (G.redirect_slide)
         wsize = G.redirect_size, redirSlide = G.redirect_buffer;